We are much indebted to Christine Wilson and Frank Israel for very kindly providing us with their single dish CO(3-2) data. F. B. thanks the Max-Planck-Institut fur Radioastronomie in Bonn, where he was a postdoc at the time of the observations, for supporting the travel to the SMA. We thank the scientific and technical staffs at the SMA for their help at the observatory. The collaboration between LERMA and ASIAA was supported by the ORCHID French-Taiwanese Hubert Curien Program.